Synchrotron SAXS

Computational methods combined with a novel approach in the application of scattering physics were recently employed by Barbi et al. in a synchrotron SAXS study of the nanostructure of Nafion as a function of mechanical load. A new method of multidimensional chord-distribution function (CDF) analysis was used to visualize the multiphase nano-... 

A variation of the lamellar model was recently proposed by Haubold et al., in which synchrotron SAXS studies were performed on acid form Nafion 117 samples. The molecular weight of these samples was reported to be 250 000 g mol and the experiments were conducted on dry samples in air and samples equilibrated with water, methanol, and a range of water/methanol mixtures using an in situ flow cell. The most fundamental result of this study is that the data show the usual ionomer peak at = 1.4 nm which gives a Bragg spacing of d= Zjtlq ... 

Figure 4. Microfocus synchrotron SAXS measurements Thickness T (nm) and Shape (rj) parameters ofcalcium-iron-phosphate features from the midden profile at Vollen, Langenesvceret, Norway. (Reproducedfrom Reference 32. Copyright 2004 Elsevier)...

Figure 10.7 Synchrotron SAXS patterns of the lamellar and columnar inverted hexagonal Hfi phases of positively charged CL/DNA complexes as => function of increasing weight fraction < DOpe- At 4>dope=0.41, the SAXS results from a single phase with the lamellar La structure sv, m in Figure 10.5. At 4>DOpe=0.7, the SAXS scan results from a single phase with the coN nar inverted h. gonal ui structure shown in Figure 10.9. At 4>DOpe=0.65, the SAXS shows coexistence of the (arrows) and Hjj phases (Adapted from Koltover etal., 1998).

Synchrotron SAXS patterns of the lamellar and columnar inverted hexagonal n 180... 

FIGURE 8.33 Schematic representation of the experimental setup used for in situ synchrotron SAXS measurements on the formation of mesoscopically ordered silicate-surfactant mesophases. The reactant solution is pumped through a thin quartz capillary and a diffractogram is recorded every 300 ms. The reaction is initiated by emulsifying a macroscopically phase-separated system of tetraethoxysUane and an aqueous phase, respectively. See text for details. 

Eisenbldtter, J., Winter, R. Pressure effects on the structure and phase behavior of DMPC-gramicidin lipid bilayers - a synchrotron SAXS and H-NMR spectroscopy study, Biophys. J. 90 (2006) 956-966. 

Recently, a unique approach for using the correlation function method has been demonstrated to extract morphological variables in crystalline polymers from time-resolved synchrotron SAXS data. The principle of the calculation is based on two alternative expressions of Porod s law using the form of interference function [33, 36]. This approach enables a continuous estimate of the Porod constant, corrections for liquid scattering... 

Time resolved SAXS/SANS allow a structural observation of kinetic processes on the nanoscale (1-100 nm) on a time scale ranging from milliseconds to hours. This allows micellar kinetics to be followed in real time, giving direct structural information of the process and its evolution. Synchrotron SAXS can reach smaller time scales and exhibits better resolution compared to neutron-based methods. However, SANS offers the possibility for contrast variation via simple H/D exchange chemistry, which opens up a world of possibilities for the investigation of kinetics in soft matter systems, in particular transport and exchange processes that otherwise would be invisible in scattering experiments. As most of these techniques have become available over recent years with advancements in both instrumentation and sample environments, there is a need for an overview of the development and the possibilities that are now available in the field of soft matter in general and micellar systems in particular. 

Schneider, K Schone, A. (2008). Online-structure characterisation of polymers during deformation and relaxation by Synchrotron-SAXS and WAXS, In Reinforced Elastomers Fracture Mechanics, Statistical Physics and Numerical Simulations Kaliske, M. Heinrich, G. Verron, E. (Eds.) EUROMECH Colloquium 502, Dresden, 2008 pp. 79-81... 

Schneider, K et al. (2009). Investigation of changes in crystalline and amorphous structure during deformation of nano-reinforced semi-crystalline polymers by space-resolved synchrotron SAXS and WAXS, Procedia Engineering Vol.l (2009), pp.l59-162... 

Ran, S. et al. (2001). Structural and morphological studies of isotactic polypropylene fibers during heat/draw deformation by in-situ synchrotron SAXS/WAXD. Macromolecules, Vol.34, Issue 8, pp. 2569-2578. 

M. Fujita, T. Sawayanagi, T. Tanaka, et aL, Synchrotron SAXS and WAXS studies on changes in structural and thermal properties of poly[(R)-3-hydroxybutyrate] single crystals during heating, Macromol. Rapid Commun., 26 (2005) 678-683. 

PLA can also be blended with PVAc. The miscibihty, the crystallization behavior and morphology of P(VAc-co-VA) has been investigated by means of differential scanning calorimetry, synchrotron SAXS techniques, polarized optical microscopy and scanning electromagnetic microscopy. 

Ran, S. F., C. Burger, I. Sics, K. W. Yoon, D. F. Fang, K. Kim, C. Avila-Orta, J. K. Keum, B. Chu, B. S. Hsiao, D. Cookson, D. Shultz, M. Lee, J. Viccaro, and Y. Ohta (2004). In situ synchrotron SAXS/WAXD studies during melt spinning of modified carbon nanofiber and isotactic polypropylene nanocomposite. Colloid and Polymer Science 282(8) 802-809. 

This work was supported by a POSTECH/BSRI special fond (1998) and the Korean Foundation of Science and Engineering ( 97-05-02-03-01-3). Synchrotron SAXS experiments at the PLS (3C2 beam line) were supported by the Ministry of Science and Technology (MOST) and Pohang Iron Steel Co. (POSCO). 

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